With present day toothbrushes, it is preferable if the cleaning surface is given a serrated profile; the bristles of the toothbrush can then penetrate better into the spaces between the teeth. The profiling of the bristle fields is usually carried out by means of a profile cutter, the contour of which is matched to the desired bristle field contour. If, for example, a serrated profile with a profile angle of 45.degree. is to be produced, a profile cutter can be used whose cutting edges are angled at 45.degree. to match the contour that is to be placed on the bristle field. This has the consequence, however, that the individual fibers of the bristle field are no longer trimmed off straight across, but are instead trimmed off pointed at a 45.degree. angle. So that the bristles do not injure the sensitive gum tissue, the pointed fiber ends must be rounded off by means of a time-consuming and sometimes machine-intensive procedure.
Stepped cutters are also already known (see German Offenlegungsschrift DE-41 38 777), by means of which the saw-toothed profile can be approximated through the use of a finely graduated stepped profile; in this way, the majority of the fibers are cut off evenly. Although this procedure and the associated apparatus offer quite a number of advantages, they also display some disadvantages. For example, it is usually impossible to prevent some of the fibers from lying in the border area that runs vertically between two steps, and thus being cut off uncleanly at the ends or even frayed. In addition, the stepped cutters are difficult and expensive to manufacture, and can be resharpened only with difficulty.
There is also an apparatus that is already known (see EP 0 078 569 A2), by means of which the fibers at the edge of a bristle field are laterally deflected towards the outside by bringing a wedge-shaped tool into the bristle field. The inner fibers, which are not deflected, can then be processed, that is for example cut off or rounded, without the processing tool coming into contact with the outer fibers. The apparatus is suitable for providing bristle fields with simple profiles, preferably those in which the fibers at the edges of the bristle field have greater lengths than the fibers in the middle of the bristle field. However, more complex profiles, especially those in which the profile running in the longitudinal direction of the brush repeats itself regularly several times, cannot in practice be manufactured, since in this case the fibers in the middle of the bristle field as well must be processed differently. This is hardly possible with the apparatus described above, since the fibers to be deflected then collide with the neighboring fibers to be processed.
A further disadvantage of the latter apparatus is that it only allows for a discontinuous mode of operation. Specifically, the processing stations are placed at regular intervals on a common carriage that is moved relative to the toothbrushes during the processing cycle. At the end of the processing cycle, the work procedure must be interrupted so that the carriage can be returned to its starting position.